全文获取类型
收费全文 | 8121篇 |
免费 | 744篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 108篇 |
儿科学 | 232篇 |
妇产科学 | 257篇 |
基础医学 | 1053篇 |
口腔科学 | 159篇 |
临床医学 | 681篇 |
内科学 | 1925篇 |
皮肤病学 | 114篇 |
神经病学 | 625篇 |
特种医学 | 271篇 |
外科学 | 1177篇 |
综合类 | 77篇 |
一般理论 | 3篇 |
预防医学 | 781篇 |
眼科学 | 132篇 |
药学 | 616篇 |
中国医学 | 22篇 |
肿瘤学 | 657篇 |
出版年
2023年 | 59篇 |
2022年 | 105篇 |
2021年 | 237篇 |
2020年 | 126篇 |
2019年 | 186篇 |
2018年 | 251篇 |
2017年 | 172篇 |
2016年 | 196篇 |
2015年 | 220篇 |
2014年 | 297篇 |
2013年 | 393篇 |
2012年 | 549篇 |
2011年 | 586篇 |
2010年 | 300篇 |
2009年 | 276篇 |
2008年 | 476篇 |
2007年 | 488篇 |
2006年 | 464篇 |
2005年 | 453篇 |
2004年 | 430篇 |
2003年 | 394篇 |
2002年 | 355篇 |
2001年 | 183篇 |
2000年 | 195篇 |
1999年 | 142篇 |
1998年 | 71篇 |
1997年 | 44篇 |
1996年 | 53篇 |
1995年 | 62篇 |
1994年 | 44篇 |
1993年 | 46篇 |
1992年 | 85篇 |
1991年 | 55篇 |
1990年 | 77篇 |
1989年 | 65篇 |
1988年 | 53篇 |
1987年 | 72篇 |
1986年 | 74篇 |
1985年 | 54篇 |
1984年 | 58篇 |
1983年 | 36篇 |
1982年 | 40篇 |
1981年 | 42篇 |
1980年 | 29篇 |
1979年 | 36篇 |
1978年 | 33篇 |
1977年 | 20篇 |
1975年 | 20篇 |
1973年 | 21篇 |
1972年 | 19篇 |
排序方式: 共有8890条查询结果,搜索用时 31 毫秒
71.
Resistance ranking of some common inbred mouse strains to Mycobacterium tuberculosis and relationship to major histocompatibility complex haplotype and Nramp1 genotype.
下载免费PDF全文
![点击此处可从《Immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Six common inbred strains of mice and their F1 hybrids were examined for resistance to infection with the H37Rv strain of Mycobacterium tuberculosis. According to survival times after inoculation of 10(5) CFU intravenously (i.v.), the mice could be classified as being either highly susceptible (CBA, DBA/2, C3H, 129/SvJ) or highly resistant (BALB/c and C57BL/6). F1 hybrids of susceptible and resistant strains were resistant. Although an examination of a limited number of H-2 congenic strains showed that the H-2k haplotype could confer susceptibility on a resistant strain, it was evident that non-major histocompatibility complex (MHC) genes were much more important. Resistant strains all possessed the susceptibility allele of the anti-microbial resistance gene, Nramp1. Results obtained with selected strains infected with 10(2) CFU of M. tuberculosis by aerosol agreed with the results obtained with mice infected i.v. The size of the bacterial inoculum was important in distinguishing between resistant and susceptible strains, in that a 10(7) inoculum overcame the resistance advantage of one strain over another. 相似文献
72.
73.
Yei-Mei Peng Ph.D. David S. Alberts Vivian Graham Earl A. Surwit Sheldon Weiner Frank L. Meyskens Jr. 《Investigational new drugs》1986,4(3):245-249
The present study was undertaken to evaluate the systemic absorption and cervical tissue uptake of all-transretinoic acid (TRA), delivered via a collagen spongecervical cap delivery device in patients with intraepithelial cervical dysplasia. Ten patients with histologically proven mild or moderate cervical dysplasia were included in this pharmacologic study. The two TRA concentrations (0.05% and 0.372%) selected for study represent the starting and maximally tolerated doses used in phase I clinical trial. All-trans-retinoic-11-3H acid (3H-TRA, 500 Ci) was used to facilitate cervical tissue uptake studies. Cervical biopsies and post-treatment blood samples were obtained from each patient after TRA exposure. The uptake of TRA into cervical tissues four hours after drug administration was significantly increased at the maximally tolerated TRA dose. There was a rapid decrease in cervical tissue concentration of TRA at the 0.372% dose between 4 and 24 h after drug exposure, suggesting a relatively short elimination half-life of TRA in cervical tissues. HPLC analysis of post-treatment blood samples indicate that there was no systemic absorption of TRA after local cervical administration. 相似文献
74.
75.
Asher Y. Rosinger Samantha M. Olson Sascha R. Ellington Janice Perez-Padilla Regina M. Simeone Caitlin S. Pedati Betsy A. Schroeder Gilberto A. Santiago Freddy A. Medina Jorge L. Muoz-Jordn Laura E. Adams Romeo R. Galang Miguel Valencia-Prado Sonia Bakkour Candimar Coln Mary Goodwin Dana Meaney-Delman Jennifer S. Read Lyle R. Petersen Denise J. Jamieson Carmen C. Deseda Margaret A. Honein Brenda Rivera-García Carrie K. Shapiro-Mendoza 《Emerging infectious diseases》2021,27(5):1505
We evaluated nucleic acid amplification testing (NAAT) for Zika virus on whole-blood specimens compared with NAAT on serum and urine specimens among asymptomatic pregnant women during the 2015–2016 Puerto Rico Zika outbreak. Using NAAT, more infections were detected in serum and urine than in whole blood specimens. 相似文献
76.
77.
Aurore Thibaut Vivian L. Shie Colleen M. Ryan Ross Zafonte Emily A. Ohrtman Jeffrey C. Schneider Felipe Fregni 《Burns : journal of the International Society for Burn Injuries》2021,47(3):525-537
Burn survivors experience myriad associated symptoms such as pain, pruritus, fatigue, impaired motor strength, post-traumatic stress, depression, anxiety, and sleep disturbance. Many of these symptoms are common and remain chronic, despite current standard of care. One potential novel intervention to target these post burn symptoms is transcranial direct current stimulation (tDCS). tDCS is a non-invasive brain stimulation (NIBS) technique that modulates neural excitability of a specific target or neural network. The aim of this work is to review the neural circuits of the aforementioned clinical sequelae associated with burn injuries and to provide a scientific rationale for specific NIBS targets that can potentially treat these conditions. We ran a systematic review, following the PRISMA statement, of tDCS effects on burn symptoms. Only three studies matched our criteria. One was a feasibility study assessing cortical plasticity in chronic neuropathic pain following burn injury, one looked at the effects of tDCS to reduce pain anxiety during burn wound care, and one assessed the effects of tDCS to manage pain and pruritus in burn survivors. Current literature on NIBS in burn remains limited, only a few trials have been conducted. Based on our review and results in other populations suffering from similar symptoms as patients with burn injuries, three main areas were selected: the prefrontal region, the parietal area and the motor cortex. Based on the importance of the prefrontal cortex in the emotional component of pain and its implication in various psychosocial symptoms, targeting this region may represent the most promising target. Our review of the neural circuitry involved in post burn symptoms and suggested targeted areas for stimulation provide a spring board for future study initiatives. 相似文献
78.
79.
Wing-Hoi Cheung Vivian Wing-Yin Hung Ka-Yee Cheuk Wai-Wang Chau Kelvin Kam-Fai Tsoi Ronald Man-Yeung Wong Simon Kwoon-Ho Chow Tsz-Ping Lam Patrick Shu-Hang Yung Sheung-Wai Law Ling Qin 《Journal of bone and mineral research》2021,36(12):2381-2398
Osteoporosis is a systemic skeletal disease characterized by low bone mass and bone structural deterioration that may result in fragility fractures. Use of bone imaging modalities to accurately predict fragility fractures is always an important issue, yet the current gold standard of dual-energy X-ray absorptiometry (DXA) for diagnosis of osteoporosis cannot fully satisfy this purpose. The latest high-resolution peripheral quantitative computed tomography (HR-pQCT) is a three-dimensional (3D) imaging device to measure not only volumetric bone density, but also the bone microarchitecture in a noninvasive manner that may provide a better fracture prediction power. This systematic review and meta-analysis was designed to investigate which HR-pQCT parameters at the distal radius and/or distal tibia could best predict fragility fractures. A systematic literature search was conducted in Embase, PubMed, and Web of Science with relevant keywords by two independent reviewers. Original clinical studies using HR-pQCT to predict fragility fractures with available full text in English were included. Information was extracted from the included studies for further review. In total, 25 articles were included for the systematic review, and 16 articles for meta-analysis. HR-pQCT was shown to significantly predict incident fractures and/or major osteoporotic fractures (MOFs). Of all the HR-pQCT parameters, our meta-analysis revealed that cortical volumetric bone mineral density (Ct.vBMD), trabecular thickness (Tb.Th), and stiffness were better predictors. Meanwhile, HR-pQCT parameters indicated better performance in predicting MOFs than incident fractures. Between the two standard measurement sites of HR-pQCT, the non-weight-bearing distal radius was a more preferable site than distal tibia for fracture prediction. Furthermore, most of the included studies were white-based, whereas very few studies were from Asia or South America. These regions should build up their densitometric databases and conduct related prediction studies. It is expected that HR-pQCT can be used widely for the diagnosis of osteoporosis and prediction of future fragility fractures. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). 相似文献
80.
Cristina García-Amador Vladimir Arteaga Peralta Roberto de la Plaza Llamas Miguel Torralba Anibal Medina Velasco José Manuel Ramia 《Cirugía espa?ola》2021,99(4):282-288
BackgroundTo analyze whether clinical and analytical parameters differ according to histopathology in cases of acute appendicitis (AA).MethodsThis is a retrospective, observational study including patients (>14 years of age) admitted for suspicion of AA from 1 April 2014 to 31 July 2016. Histopathology was divided into complicated (including perforated and gangrenous AA) and uncomplicated appendicitis (phlegmonous). Sex, age, temperature of patients on admission to the Emergency Department, symptom duration, preoperative white blood cell (WBC) count, neutrophil percentage, mean platelet volume (MPV), platelet distribution width (PDW), C-reactive protein (CRP) and hospital stay were compared in the two groups.ResultsThree hundred and thirty-five patients were analyzed, and 284 were included. Appendicitis was uncomplicated in 194 (68.3%) and complicated in 90 (31.7%). Age, symptom duration, neutrophil percentage, CRP and hospital stay were higher in the complicated AA group (P < .05). The mean differences between uncomplicated and complicated AA were: age 13.2 years (95% CI: 8.2-18.2), symptom duration 14.1 hours (95% CI: 6.3-21.9), neutrophil percentage 5.0% (95% CI: 3.2-6.8), CRP 73.6 mg/l (95% CI: 50.0-97.2) and hospital stay 2.2 days (95% CI: 1.4-3.0), with p<0.05 for all these variables. A model based on the preoperative parameters (age, symptom duration, neutrophil percentage and CRP) was calculated to predict the likelihood of complicated AA. The receiver operating characteristic (ROC) of the model had an area under the curve of 0.80 (95% CI 0.75-0.85).ConclusionThis model is able to diagnose complicated AA without the need for imaging techniques, although it must be validated with prospective analysis. 相似文献